1. Field of the Invention
The present invention relates to an amorphous oxide magnetic material having ferromagnetism.
2. Description of the Related Art
An amorphous magnetic material has physical characteristics not found in a crystal material and therefore is studied at many organizations. A typical example of the amorphous magnetic material is an amorphous magnetic alloy obtained by rapid quenching a melted material formed of a metal element such as Co, Fe, or Ni and a semimetal element such as Si or B. Since the amorphous magnetic material has good magnetic characteristics, it is used in various fields such as a magnetic head and a switching power supply. An amorphous alloy thin film formed of Fe or Co and a rare earth element is widely studied as a magneto-optical recording medium. However, essentially, the amorphous magnetic alloy is easily oxidized and has low stability.
An oxide magnetic material is expected as a highly stable magnetic material. However, not so many oxide magnetic materials having ferromagnetism at room temperature or more have been found.
As examples of the oxide magnetic material having ferromagnetism, Fe.sub.2 O.sub.3 -TO-X (wherein T represents Ca, Ba, Zn, or Mg and X represents Bi.sub.2 O.sub.3, B.sub.2 O.sub.3, or SiO.sub.2) and MFe.sub.2 O.sub.4 -P.sub.2 O.sub.5 mainly consisting of spinel MFe.sub.2 O.sub.4 (wherein M represents Fe, Co, Ni, Mn, Cu, or Mn-Zn) are reported (e.g., Journal of Functional Material, April 1984, p. 1, J. Mag. Mag. Mater. 54-57 (1986)296, Journal of Applied Physics, Vol. 56, No. 5, p. 596). Either of these materials is an amorphous oxide mainly consisting of an oxide of Fe, is attracted to a magnet, and therefore is assumed to be a ferromagnetic material. However, a Moesbauer spectrum of either of the materials exhibits paramagnetism at room temperature. This indicates that these materials do not have a so-called ferromagnetic spin arrangement.
That is, no effective amorphous oxide material having ferromagnetism has been found.